Conventionally, an optical transmission system using light as a signal medium has been used to perform high-speed and long-distance communication. In the above-described optical transmission system, a waveform of an optical signal is deteriorated by chromatic dispersion due to characteristics of the optical transmission path. When the wavelength of the optical signal is deteriorated, there is a high possibility that a transmission error occurs with respect to an original signal included in the optical signal. Therefore, for the optical transmission system, a technique has been developed to compensate for chromatic dispersion generated on the optical transmission path by a variable dispersion compensator located in a receiving unit of an optical transmission device that transmits and receives the optical signal.
For example, a dispersion compensation device that controls a dispersion compensation amount of the variable dispersion compensator has been developed based on code error information of a signal that is output through an optical reception path from the variable dispersion compensator. Moreover, a dispersion compensation method for controlling the dispersion compensation amount of the variable dispersion compensator according to the code error information in accordance to a code type in a data signal obtained by receiving a dispersion-compensated optical signal has been developed.
The conventional techniques are disclosed in Japanese Laid-open Patent Publication No. 2002-208892 and Japanese Laid-open Patent Publication No. 2005-286382.